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No. 15/July 06, 2001

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IN THIS ISSUE:
Field Crop Session to Focus on Insects
Crop producers, agribusiness dealers, and field scouts are invited to participate in an "Insect Management--Past, Present, and Future" workshop on July 26. The focus of the workshop will be on management strategies and tactics for insects currently affecting field crops and for those that may affect crops later in the season.

Some of the insects to be discussed include armyworm, corn rootworms, soybean aphid, and potato leafhopper. The workshop will include classroom discussion and in-field demonstrations.

Soybean Aphids Are Becoming More Prevalent
Survey teams continue to "discover" soybean aphids in soybean fields in northern and east-central Illinois. Now that we are finding soybean aphids in soybean fields, we will focus on some other research objectives. A new focus will be to monitor aphid population dynamics weekly in selected fields to determine whether densities are increasing or decreasing and to assess the impact of natural mortality factors, including predators, parasitoids, and pathogens.

We still believe it is too early to consider insecticide applications to control soybean aphids. However, it's not too early to start looking for them. The relatively large numbers of aphids found in some fields suggest that threatening densities could occur soon.

Twospotted Spider Mites Are Noticeable in Some Areas
The hot, dry weather that has predominated in some areas of Illinois has enabled twospotted spider mites to gain a foothold in some soybean fields. Unless we get some rainfall in dry areas of the state, twospotted spider mites probably will become established and their population densities will increase. Therefore, we strongly encourage you to start looking for these pests that are notoriously associated with droughty conditions.

More Reports of Odd Lepidoptera Creatures
Last week's issue of the Bulletin discussed thistle caterpillars (the adults are painted lady butterflies) and whitelined sphinx caterpillars being found in some crop fields in Illinois. Now others have found these odd creatures, too.

Japanese Beetles Are Making Their Presence Known
We have received many reports of very large numbers of Japanese beetles in cornfields and soybean fields in several areas of Illinois. During the next few weeks in pollinating cornfields, watch for Japanese beetles (and corn rootworm adults) that might clip silks and interfere with pollination. Japanese beetles also will defoliate soybeans.

Another Weird One to Watch For: False Chinch Bugs?
Add this one to a growing list of oddball insect occurrences that have characterized 2001. Although false chinch bugs are content to feed on a number of different weed species, they will feed on field crops when their weed hosts dry up. Obviously this can occur in areas of the state that have been hot and dry for an extended period.

Diseases?
Corn is tasseling or starting to tassel. This is the time to scout for foliar disease in corn. The weather has been too dry in most areas for much disease development this year, but if foliar diseases develop in the next few weeks, remember that a threshold exists. For leaf blights, including the rust fungi, it is not the individual identity of the blight that is important but rather the percentage of leaf area blighted as a whole on the entire plant.

Callisto Corn Size Limits
We have had several questions about applying Callisto with drops for control of large broadleaf weed species. Callisto is labeled for use in corn up to 30 inches in height or up to the 8-leaf stage. It is not labeled for applications when the corn is tasseling, as some have asked about.

It's Back Again in 2001
This time of year, we typically encounter soybean fields with cupped or "puckered" leaves. The 2001 season is proving to be very similar to previous seasons, in that many soybean fields are demonstrating this strange phenomenon.

This article examines several theories that have been put forward concerning the cause of this condition.

Regional Reports
Extension Center educators, Unit educators, and Unit assistants in northern, west-central, east-central, and southern Illinois prepare regional reports to provide more localized insight into pest situations and crop conditions in Illinois. The reports will keep you up to date on situations in field and forage crops as they develop throughout the season.

This week's issue includes reports from northern, southern, and west-central Illinois.



The Pest Management and Crop Development Bulletin
Executive Editor: Kevin Steffey, Extension Entomologist

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